Re: [PATCHv1 1/4] dt-bindings: display: panel-dsi-cm: convert to YAML

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Sebastian,

Thank you for the patch.

On Tue, Jun 30, 2020 at 07:50:31AM +0200, Sam Ravnborg wrote:
> On Tue, Jun 30, 2020 at 12:33:12AM +0200, Sebastian Reichel wrote:
> > Convert panel-dsi-cm bindings to YAML and add
> > missing properties while at it.
> > 
> > Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> 
> Thanks, one of the few panel bindings still pending.
> And you added some nice explanations too, good.
> 
> Some small comments in the folllowing.
> 
> > ---
> >  .../bindings/display/panel/panel-dsi-cm.txt   |  29 -----
> >  .../bindings/display/panel/panel-dsi-cm.yaml  | 100 ++++++++++++++++++
> >  2 files changed, 100 insertions(+), 29 deletions(-)
> >  delete mode 100644 Documentation/devicetree/bindings/display/panel/panel-dsi-cm.txt
> >  create mode 100644 Documentation/devicetree/bindings/display/panel/panel-dsi-cm.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/display/panel/panel-dsi-cm.txt b/Documentation/devicetree/bindings/display/panel/panel-dsi-cm.txt
> > deleted file mode 100644
> > index dce48eb9db57..000000000000
> > --- a/Documentation/devicetree/bindings/display/panel/panel-dsi-cm.txt
> > +++ /dev/null
> > @@ -1,29 +0,0 @@
> > -Generic MIPI DSI Command Mode Panel
> > -===================================
> > -
> > -Required properties:
> > -- compatible: "panel-dsi-cm"
> > -
> > -Optional properties:
> > -- label: a symbolic name for the panel
> > -- reset-gpios: panel reset gpio
> > -- te-gpios: panel TE gpio
> > -
> > -Required nodes:
> > -- Video port for DSI input
> > -
> > -Example
> > --------
> > -
> > -lcd0: display {
> > -	compatible = "tpo,taal", "panel-dsi-cm";
> > -	label = "lcd0";
> > -
> > -	reset-gpios = <&gpio4 6 GPIO_ACTIVE_HIGH>;
> > -
> > -	port {
> > -		lcd0_in: endpoint {
> > -			remote-endpoint = <&dsi1_out_ep>;
> > -		};
> > -	};
> > -};
> > diff --git a/Documentation/devicetree/bindings/display/panel/panel-dsi-cm.yaml b/Documentation/devicetree/bindings/display/panel/panel-dsi-cm.yaml
> > new file mode 100644
> > index 000000000000..8d6a20f26470
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/display/panel/panel-dsi-cm.yaml
> > @@ -0,0 +1,100 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only or BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/display/panel/panel-dsi-cm.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: DSI command mode panels
> > +
> > +maintainers:
> > +  - Tomi Valkeinen <tomi.valkeinen@ti.com>
> > +  - Sebastian Reichel <sre@kernel.org>
> > +
> > +description: |
> > +  This binding file is a collection of the DSI panels that
> > +  are usually driven in command mode. If no backlight is
> > +  referenced via the optional backlight property, the DSI
> > +  panel is assumed to have native backlight support.
> 
> > +  The panel may use an OF graph binding for the association
> > +  to the display, or it may be a direct child node of the
> > +  display.
> 
> Later port: is required which does not really match this explanation.
> 
> > +
> > +allOf:
> > +  - $ref: panel-common.yaml#
> > +
> > +properties:
> > +
> > +  compatible:
> > +    items:
> > +      - enum:
> > +        - motorola,droid4-panel        # Panel from Motorola Droid4 phone
> > +        - nokia,himalaya               # Panel from Nokia N950 phone
> > +        - tpo,taal                     # Panel from OMAP4 SDP board
> > +      - const: panel-dsi-cm            # Generic DSI command mode panel compatible fallback
> > +
> > +  reg:
> > +    maxItems: 1
> > +    description: DSI virtual channel
> > +
> > +  vddi-supply:
> > +    description:
> > +      Display panels require power to be supplied. While several panels need
> > +      more than one power supply with panel-specific constraints governing the
> > +      order and timings of the power supplies, in many cases a single power
> > +      supply is sufficient, either because the panel has a single power rail, or
> > +      because all its power rails can be driven by the same supply. In that case
> > +      the vddi-supply property specifies the supply powering the panel as a
> > +      phandle to a regulator.
> > +
> > +  vpnl-supply:
> > +    description:
> > +      When the display panel needs a second power supply, this property can be
> > +      used in addition to vddi-supply. Both supplies will be enabled at the
> > +      same time before the panel is being accessed.
> > +
> > +  width-mm: true
> > +  height-mm: true
> > +  label: true
> > +  rotation: true
> > +  panel-timing: true
> > +  port: true
> > +  reset-gpios: true
> > +  te-gpios: true
> > +  backlight: true
> > +
> > +additionalProperties: false
> > +
> > +required:
> > +  - compatible
> > +  - port
> > +  - reg
> > +
> > +examples:
>
> My personal preference is indent 4 spaces.
> But there is no hard rule so do what you like.
> 
> > +  - |
> > +    #include <dt-bindings/gpio/gpio.h>
> > +
> > +    dsi-controller {
> > +      #address-cells = <1>;
> > +      #size-cells = <0>;
> > +
> > +      port {
> > +        dsi1_out_ep: endpoint {
> > +          remote-endpoint = <&lcd0_in>;
> > +          lanes = <0 1 2 3 4 5>;
> > +        };
> > +      };
> 
> Addding the port node here does not really help me,
> I was left confused about the lanes = <...> property.
> 
> > +
> > +      panel@0 {
> > +        compatible = "tpo,taal", "panel-dsi-cm";
> > +        label = "lcd0";
> 
> This use of label does not really match the description.
> The description says label shall be used for specific names and not
> generic names like "lcd".
> 
> > +        reg = <0>;
> > +        reset-gpios = <&gpio4 6 GPIO_ACTIVE_HIGH>;
> > +
> > +        port {
> > +          lcd0_in: endpoint {
> > +            remote-endpoint = <&dsi1_out_ep>;
> > +          };
> > +        };
> > +      };
> > +
> > +    };
> 
> Add:
> <empty line>
> ...
> 
> The latter is end of statement or soething.
> You see it used often bu not always.
> 
> I expect it to become mandatory the day the tools check for it.

I have no other comment to add. Once you address the issues pointed out
by Sam, you can add my

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

-- 
Regards,

Laurent Pinchart
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